Sets up the folder structure for adding Scratch 2.0 versions of the lessons and makes the first changes

This pull request sets up the folder structure for Scratch 2.0 versions of Term 1. A new folder, Term 1 Scratch 2.0, sites next to the Term 1 folder within en-gb.

Then, I've made an additional change to remove references to the FOREVER IF block that is no longer supported in Scratch 2.0.

If you've rather see a bigger set of changes build up before you accept a pull request then that's fine, but I wanted you guys to sanity check that the structure and approach to these changes is what you're after before spending more time on this.

If you're happy with the approach, but want to see a bigger set of changes before pulling this into the master branch, feel free to reject this pull request.